[apple/xnu.git] / osfmk / man / device_write_async.html

<h2>device_write_async</h2>\r<hr>\r<p>\r<strong>System Trap</strong> - Write a sequence of bytes to a device object.\r<h3>SYNOPSIS</h3>\r<pre>\r<strong>kern_return_t   device_write_async</strong>\r                <strong>(mach_port_t</strong>                             <var>device</var>,\r                 <strong>mach_port_t</strong>                              <var>queue</var>,\r                 <strong>mach_port_t</strong>                         <var>request_id</var>,\r                 <strong>dev_mode_t</strong>                                <var>mode</var>,\r                 <strong>recnum_t</strong>                                <var>recnum</var>,\r                 <strong>io_buf_ptr_t</strong>                              <var>data</var>,\r                 <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var><strong>);</strong>\r</pre>\r<h3>PARAMETERS</h3>\r<dl>\r<p>\r<dt> <var>device</var>\r<dd>\r[in device send right] A device port to the device to be read.\r<p>\r<dt> <var>queue</var>\r<dd>\r[in io_done queue send right] The port returned from \rio_done_queue_create.\r<p>\r<dt> <var>request_id</var>\r<dd>\r[in send right] An unique request identifier that will be passed back as \rpart of the io_done_result structure.\r<p>\r<dt> <var>mode</var>\r<dd>\r[in scalar] I/O mode value. Meaningful options are:\r<p>\r     <dl>\r<dt> <strong>D_NOWAIT</strong>\r<dd>\rDo not wait if data is unavailable.\r     </dl>\r<p>\r<dt> <var>recnum</var>\r<dd>\r[in scalar] Record number to be read.\r<p>\r<dt> <var>data</var>\r<dd>\r[pointer to in array of bytes] Data bytes to be written.\r<p>\r<dt> <var>bytes_wanted</var>\r<dd>\r[in scalar] Size of data transfer.\r</dl>\r<h3>DESCRIPTION</h3>\r<p>\rThe <strong>device_write_async</strong> function enqueues a write operation for a\rsequence of bytes to a device object. The meaning of recnum as well as\rthe specific operation performed is device dependent.\r<h3>RETURN VALUES</h3>\r<p>\r<strong>device_write_async</strong> returns only invalid parameter errors.\r<h3>RELATED INFORMATION</h3>\r<p>\rFunctions:\r<a href="device_read_async_inband.html"><strong>device_read_async_inband</strong></a>,\r<a href="DR_overwrite_async.html"><strong>device_read_overwrite_async</strong></a>,\r<a href="device_write_async_inband.html"><strong>device_write_async_inband</strong></a>,\r<a href="io_done_queue_create.html"><strong>io_done_queue_create</strong></a>.\r